code: def _clean_input(input):
      def _clean_layer(layer):
          # Remove some keys
          layer.pop("stat", None)
          layer.pop("data_meta", None)
          layer.pop("mapping", None)
          layer.pop("show_legend", None)
  
      layers = input.get("feature-list", None)
      if layers:
          for l in layers:
              _clean_layer(l["layer"])
      else:
          _clean_layer(input)
  
file_path: lets-plot/python-package/test/plot/test_marginal_layer.py
imports: import pytest
  import lets_plot
label_desc: Use image node_id 6 for calling a global function with example usage: _clean_input(input) without return types